For improving performance of aerospace system, more accurate control method is need, the co-simulation use advantages of each platform to supply more accurate system model and make algorithm more real and useful. By many researches on Simulink, AMESim and Flowmaster, co-simulation system of AMESim/Flowmaster on Simulink main platform is proposed in this paper. The co-simulation technology use interfaces of Simlink and AMESim/ flowmaster to call AMESim/Flowmaster system module, then introduce implementation steps of every interface of Simulink and AMESim/Flowmaster. And realize a co-simulation example at the same time. The research results show that the research can solves problem of simulation interface model compatibility and expansibility.